The invention relates to a device and a method for forming CO2, N2 and/or SO2 from a sample for quantitative analysis of the sample, having a reactor structure and metals or metal oxides acting in an oxidizing manner on carbon in the reactor structure. Preferably, the sample is an organic sample, a derivative of an organic sample or generally a GC-handleable substance. In addition, the invention relates to a use of the device.
Reference is made to the disclosure in U.S. Pat. No. 5,432,344 and to the publication DE 42 32 301 A of the associated first German filing. These documents are incorporated in entirety in the disclosure of the present invention. The documents concern an appliance for isotope ratio analysis, having a gas chromatograph, a combustion furnace and a mass spectrometer. A sample is resolved in the gas chromatograph into single gaseous components which are intended to be reduced in the combustion furnace to simple gases. The latter must be suitable for analysis in the mass spectrometer. In particular, the formation of CO2 and/or N2 is intended or possible. The formation of SO2 from sulfur-containing compounds is also conceivable. The gas coming from the gas chromatograph flows through the combustion furnace and is oxidized in the course of this. In the combustion furnace, as an aid for the oxidation, nickel oxide is provided, optionally in combination with copper oxide.
The combustion furnace has only a restricted service life. After a certain amount of gas has passed through, the metal oxide present in the combustion furnace is consumed to the extent that the measurement results are no longer satisfactory. Reoxidation of the metal is necessary. Extension of the service life or of the reoxidation intervals is sought.
Nitrogen oxides are also formed from the sample in the combustion furnace. These nitrogen oxides are customarily converted in a downstream reduction reactor to N2. The additional reduction reactor increases the complexity of apparatus of the overall system.